The "check_svn" plugin worked from the command line. However when I attempted to configure the Nagios check, an error occurred.
Ref: http://www.nagiosexchange.org/cgi-bin/page.cgi?g=Detailed%2F1554.html;d=1
SVN CRITICAL: Error connecting to svn server - Can't open file '/root/.subversion/servers': Permission denied .
Solutions
Apparently this is caused by nagios environment issue. The nagiosexchange page recommends one solution. Alternatively you can modify the check_svn script.
command_line export HOME=/home/nagios && $USER1$/check_svn if self.confdir:
cmd += " --config-dir=%s" % self.confdirAll should work well now. I also make sure to use the "-T" option to output the test execution time which I can now graph with nagiosgraph.